Over 90 per cent of COVID-19 cases are occurring in urban areas. The pandemic is hitting the most vulnerable the hardest, including the 1 billion residents of the world’s densely populated informal settlements and slums. Even before the new coronavirus, rapid urbanization meant that 4 billion people in the world’s cities faced worsening air pollution, inadequate infrastructure and services, and unplanned urban sprawl. Safe public transportation, reliable basic services and open public spaces are especially important now to ensure the health and livelihoods of urban dwellers. Successful examples of containing COVID-19 demonstrate the remarkable resilience and adaptability of urban communities in adjusting to new norms. Cities will emerge from the pandemic, but whether they are prepared for the next crisis will depend on how much they can advance data-driven inclusive and sustainable urban development.